Case study of power allocation strategy for a grid-side lead-carbon battery energy storage system

Abstract

Battery energy storage system (BESS) is an important component of future energy infrastructure with significant renewable energy penetration. Lead-carbon battery is an evolution of the traditional lead-acid technology with the advantage of lower life cycle cost and it is regarded as a promising candidate for grid-side BESS deployment. However, inconsistency among lead-carbon batteries in a BESS is a major concern which has to be carefully considered in practical operation. One of the available approaches to relieve this issue is to develop a sophisticated power allocation strategy (PAS) among multiple converters inside the BESS. This work conducts a comprehensive case study on the impact of PAS in a grid-side 12 MW/48 MWh BESS recently constructed in Zhejiang, China (Zhicheng energy storage station, the first grid-side lead-carbon BESS in China). Three different PASs (i.e. averaged, state weighted and state prioritized) are investigated and benchmarked with two typical BESS application scenarios of peak shaving and frequency regulation, from real-world experiments using the aforementioned BESS. The performance of the strategies is quantitatively evaluated by three indices defined in this work. The state prioritized strategy is found to be the most effective for this lead-carbon BESS.